JP2604223B2 - Thermal recording material - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a heat-sensitive recording material, and more particularly to a diazo-based heat-sensitive recording material that can be fixed. More specifically, the present invention relates to a heat-sensitive recording material which has excellent preservability before thermal recording, has a fast thermal response during thermal recording, and can be optically fixed after thermal recording.

"Prior art" A leuco coloring type thermosensitive recording material is usually used as a recording material used in a thermosensitive recording method. However,
This heat-sensitive recording material has a drawback that coloring occurs in unexpected places due to severe handling, heating or adhesion of a solvent after recording, and the recorded image is stained. In recent years, as a heat-sensitive recording material free from such defects, research on a diazo-coloring-type heat-sensitive recording material has been actively conducted. For example, JP-A-57-1230
No. 86, Journal of the Institute of Image Electronics Engineers of Japan, 11 , 290 (1982), etc., but it is applicable to recording materials using a diazo compound, a coupling component, and a basic component (including a substance which becomes basic by heat). Heat recording is performed, and then light irradiation is performed to decompose unreacted diazo compounds to stop color development.
Certainly, according to this method, it is possible to stop coloring (hereinafter, referred to as “fixing”) of a portion that does not require recording. However, pre-coupling of this recording material also proceeds gradually during storage, and undesired coloring (fog) may occur. In order to solve this problem, we first disclosed in, for example,
As disclosed in Japanese Patent No. 2675, etc., at least one of the components involved in the color-forming reaction is contained in a core material, and a wall is formed around the core material by polymerization to form microcapsules. It was found that an excellent heat-sensitive recording material could be obtained.

However, even in the heat-sensitive recording material obtained by this microencapsulation method, the thermal responsiveness during high-speed recording cannot be said to be sufficient, and the storage stability before thermal recording has not been sufficient.

[Object of the invention]

Accordingly, an object of the present invention is to provide a heat-sensitive recording material which is excellent in raw preservability, has a fast thermal response, and can be optically fixed after thermal recording.

[Means for solving the problem]

The present inventors have conducted intensive studies and found that a thermosensitive recording material having a recording layer containing a diazo compound and a coupling component on a support had a solubility in water at 50 ° C of 1.5 g / 1.
The object has been achieved by using a thermosensitive recording material characterized by containing not more than 00 ml of an α-aryloxyacetamide derivative.

Preferably, either the diazo compound or the coupling component is contained in a microcapsule.

The microcapsule of the present invention is broken by heat or pressure as in the conventional recording material, and the reactive substance contained in the core of the microcapsule is brought into contact with the reactive substance outside the microcapsule. However, it does not cause a color-forming reaction by heating, but reacts mainly by passing through the microcapsule wall by heating a reactive substance present on the core and outside of the microcapsule.

In the present invention, the particle size of the microcapsules is set to 2
By combining with a specific amide below μ,
The sensitivity can be improved without increasing fog of the thermosensitive recording material using these. Preferably
1.5μ or less.

The present inventors have conducted intensive studies on a thermosensitive recording material using such microcapsules, and as a result, have excellent raw preservability, improved thermochromic properties, and an optical density of a recorded image by long-term storage after thermal recording. In order to prevent the deterioration, a specific amide in the layer besides the diazo component and the coupling component is used.
It has been found that the inclusion of an α-aryloxyacetamide derivative having a solubility in water at 50 ° C. of 1.5 g / 100 ml or less is extremely effective.

Preferred examples of the α-aryloxyacetamide derivative in the present invention include a compound represented by the following general formula (I).

In the above formula, R ¹ and R ² each independently represent a hydrogen atom, an alkyl group, an alkoxy group, an aryl group or a halogen atom, and R ³ represents a hydrogen atom, an alkyl group or an aryl group. Further, in the above formula, ^one of R ¹ and R ² is preferably not a hydrogen atom, and in particular, a methyl group, a methoxy group, a fluorine atom, a chlorine atom and the like are preferable.

 Examples of specific compounds are as follows.

α- (2-methylphenoxy) acetamide, α-
(3-methylphenoxy) acetamide, α- (4-methylphenoxy) acetamide, α- (2-methoxyphenoxy) acetamide, α- (3-methoxyphenoxy) acetamide, α- (4-methoxyphenoxy) Acetamide, α- (2-fluorophenoxy) acetamide, α- (3-fluorophenoxy) acetamide,
α- (4-fluorophenoxy) acetamide, α-
(2-chlorophenoxy) acetamide, α- (3-chlorophenoxy) acetamide, α- (4-chlorophenoxy) acetamide, α-phenoxy-N-benzylacetamide.

The diazo compound used in the present invention has the general formula ArN ₂ ⁺ X ⁻
(In the formula, Ar represents an aromatic moiety, N ₂ ⁺ represents a diazonium group, and X ⁻ represents an acid anion.) A diazonium salt represented by the following formula ^: And compounds that can be decomposed by light.

Specifically, the aromatic moiety preferably has the following general formula.

In the formula, Y is a hydrogen atom, a substituted amino group, an alkoxy group,
Represents an aryloxy group, an arylthio group, an alkylthio group or an acylamino group, and R represents a hydrogen atom, an alkyl group, an alkoxy group, an aryloxy group, an arylamino group, or a halogen (I, Br, Cl, F). n is 1 or 2
Represents

As the substituted amino group for Y, a monoalkylamino group,
Dialkylamino, arylamino, morpholino, piperidino, pyrrolidino and the like are preferred.

Specific examples of the salt-forming diazonium include 4-diazo-1-dimethylaminobenzene and 4-diazo-1-
Diethylaminobenzene, 4-diazo-1-dipropylaminobenzene, 4-diazo-1-methylbenzylaminobenzene, 4-diazo-1-dibenzylaminobenzene, 4-diazo-1-ethylhydroxyethylaminobenzene, 4- Diazo-1-diethylamino-3-methoxybenzene, 4-diazo-1-dimethylamino-2-methylbenzene, 4-diazo-1-benzoylamino-2,
5-diethoxybenzene, 4-diazo-1-morpholinobenzene, 4-diazo-1-morpholino-2,5-diethoxybenzene, 4-diazo-1-morpholino-2,5-dibutoxybenzene, 4-diazo -1-anilinobenzene, 4-diazo-1-toluylmercapto-2,5-diethoxybenzene, 4-diazo-1,4-methoxybenzoylamino-2,5-diethoxybenzene, 4-diazo-1
-Pyrrolidino-2-ethylbenzene and the like.

Specific examples of the acid anion include CnF _{2n + 1} COO ⁻ (n is an integer of 3 to 9), CmF _{2m + 1} SO ₃ ⁻ (m is an integer of 2 to 8), and (ClF _{2l + 1} SO ₂ ) ₂ CH ^- (l 1 to 18 _{integer), B (C 6 H 5} ) 4 -, BF ₄ ^-, PF ₆ ^-, and the like.

In particular, as the acid anion, those containing a perfluoroalkyl group or a perfluoroalkenyl group or PF ₆ ^- are preferable since they do not increase fog during raw storage.

Specific examples of the diazo compound (diazonium salt) include:
For example, the following examples are given.

The coupling component used in the present invention is one that couples with a diazo compound (diazonium salt) in a basic atmosphere to form a dye. Specific examples thereof include resorcinol, phloroglucin, 2,3-dihydroxynaphthalene-6-sulfonic acid. Sodium, 1-hydroxy-2-
Naphthoic acid morpholinopropylamide, 1,5-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,3-
Dihydroxy-6-sulfanylnaphthalene, 2-hydroxy-3-naphthoic acid morpholinopropylamide, 2
-Hydroxy-3-naphthoic acid anilide, 2-hydroxy-3-naphthoic acid-2'-methylanilide, 2-hydroxy-3-naphthoic acid ethanolamide, 2-hydroxy-3-naphthoic acid octylamide, 2-hydroxy- 3-naphthoic acid-N-dodecyl-oxy-propylamide, 2-hydroxy-3-naphthoic acid tetradecylamide, acetanilide, acetoacetanilide, benzoylacetanilide, 1-phenyl-3-methyl-5-
Pyrazolone, 1- (2 ', 4', 6'-trichlorophenyl) -3-benzamide-5-pyrazolone, 1-
(2 ', 4', 6'-Trichlorophenyl) -3-anilino-5-pyrazolone, 1-phenyl-3-phenylacetamido-5-pyrazolone and the like. Further, by using two or more of these coupling components, an image having an arbitrary color tone can be obtained.

It is preferable to add a basic substance to the heat-sensitive recording material of the present invention in order to promote color formation. Examples of the basic substance include a poorly water-soluble or water-insoluble basic substance and a substance that generates an alkali by heating. Used.

Basic substances include inorganic and organic ammonium salts,
Organic amines, amides, ureas and thioureas and their derivatives,
Nitrogen-containing compounds such as thiazoles, pyrroles, pyrimidines, piperazines, guanidines, indoles, imidazoles, imidazolines, triazoles, morpholines, piperidines, amidines, formazines, pyridines and the like. Specific examples of these include, for example, ammonium acetate, tricyclohexylamine, tribenzylamine, octadecylbenzylamine, stearinamine, allylurea, thiourea, methylthiourea, allylthiourea, ethylenethiourea, 2-benzylimidazole, 4-phenyl Imidazole, 2-
Phenyl-4-methyl-imidazole, 2-undecyl-imidazoline, 2,4,5-trifuryl-2-imidazoline, 1,2-diphenyl-4,4-dimethyl-2-imidazoline, 2-phenyl-2-imidazoline, 1,2,3-triphenylguanidine, 1,2-ditolylguanidine, 1,2-dicyclohexylguanidine, 1,2,3-tricyclohexylguanidine, guanidine trichloroacetate, N, N'-
Dibenzylpiperazine, N, N'-diphenethylpiperazine, N, N-bis (2-phenoxyethyl) piperazine,
N, N'-bis [2- (4-methoxyphenoxy) ethyl] piperazine, N, N'-bis [2- (4-ethylphenoxy) ethyl] piperazine, N, N'-bis (3-phenoxy Cypropyl) piperazine, N, N'-bis [3- (4
-Methoxyphenoxy) propyl] piperazine, N, N '
-Bis [3- (4-ethylphenoxy) propyl] piperazine, N, N'-bis (3-phenoxy-2-hydroxypropyl) piperazine, N, N'-bis [3- (4-methylphenoxy) -2-hydroxy Propyl] piperazine, N, N'-bis [3- (4-methoxyphenoxy)-
2-hydroxypropyl] piperazine, N, N'-bis (3-phenylthio-2-hydroxypropyl) piperazine, N, N'-bis [3- (β-naphthoxy) -2-hydroxypropyl] piperazine, N-3 -(Β-naphthoxy) -2-hydroxypropyl-N′-methylpiperazine, N-3- (β-naphthoxy) -2-hydroxypropylmorpholine, 1,4-bis (3-morpholino-2-
Hydroxypropyloxy) benzene, 1,3-bis (3
-Morpholino-2-hydroxypropyloxy) benzene, 1,4-bis [3- (N-methylpiperazino) -2-
[Hydroxypropyloxy] benzene, 4,4'-dithiomorpholine, morpholinium trichloroacetate, 2-amino-benzothiazole, 2-benzoylhydrazino-
There is benzothiazole. These basic substances can be used in combination of two or more kinds.

In the present invention, a reactive substance contained in a core substance of a microcapsule is dissolved or dispersed in a water-insoluble organic solvent, and after emulsification, a microcapsule wall is formed therearound by polymerization. Are preferably those having a boiling point of 180 ° C. or higher. Specifically, phosphoric acid esters, phthalic acid esters, other carboxylic acid esters, fatty acid amides, alkylated biphenyls, alkylated terphenyls, chlorinated paraffins, alkylated naphthalenes, diarylethanes and the like are used. Specific examples include tricresyl phosphate, trioctyl phosphate, octyl diphenyl phosphate, tricyclohexyl phosphate, dibutyl phthalate,
Dioctyl phthalate, dilauryl phthalate, dicyclohexyl phthalate, butyl oleate, diethylene glycol dibenzoate, dioctyl sebacate, dibutyl sebacate, dioctyl adipate, trioctyl trimellitate, acetyl triethyl citrate, octyl maleate, dibutyl maleate, isopropyl Biphenyl, isoamyl biphenyl, chlorinated paraffin, diisopropyl naphthalene, 1,1'-ditolyl ethane, 2,4-di-tert-aminophenyl, N, N-dibutyl-2-butoxy-5-tert-octyl aniline and the like. Can be

Among them, ester solvents such as dibutyl phthalate, tricresyl phosphate, diethyl phthalate, and dibutyl maleate are particularly preferable.

The microcapsules of the present invention are produced by emulsifying a core substance containing a reactive substance and then forming a wall of a polymer substance around the oil droplets. The reactant that forms the polymeric substance is added inside the oil droplet and / or outside the oil droplet. Specific examples of the polymer substance include polyurethane, polyurea, polyamide, polyester, polycarbonate, uric acid-formaldehyde resin, melamine resin, polystyrene, styrene methacrylate copolymer, styrene-acrylate copolymer, gelatin, polyvinylpyrrolidone,
Polyvinyl alcohol and the like.

Two or more polymer substances can be used in combination. Preferred polymeric substances are polyurethanes, polyureas, polyamides, polyesters, polycarbonates, more preferably polyurethanes and polyureas.

As for the method of forming the microcapsule wall of the present invention, especially when a microencapsulation method by polymerization of a reactant from the inside of an oil droplet is used, the effect is large. That is, it is possible to obtain a capsule having a uniform particle size in a short period of time and which is preferable as a recording material having excellent raw preservability.

This technique and specific examples of compounds are described in U.S. Patent
Nos. 3,726,804 and 3,796,669.

For example, when polyurethane is used as a capsule wall material, a polyvalent isocyanate and a second substance (e.g., polyol) which reacts with the polyisocyanate to form a capsule wall are mixed in an oily liquid to be encapsulated, emulsified and dispersed in water, and then the temperature is lowered. By ascending, a polymer-forming reaction occurs at the oil droplet interface to form a microcapsule wall. At this time, an auxiliary solvent having a low boiling point and strong dissolving power can be used in the oily liquid.

In this case, the polyisocyanate to be used and the polyol and polyamine to be reacted therewith are described in U.S. Pat. Nos. 3,281,383, 3,773,695, 3,793,268, and JP-B-48-78.
Nos. -40347 and 49-24159, JP-A-48-80191 and 48
No. 84086, which can also be used.

Further, a tin salt or the like can be used in combination to promote the urethanization reaction.

In particular, a polyvalent isocyanate is used as the first wall film forming substance,
It is preferable to use a polyol as the second wall-film-forming substance because of good raw preservability. Further, by combining the two, the heat permeability of the reactive substance can be arbitrarily changed.

Examples of the polyvalent isocyanate that is the first wall film forming substance include m-phenylene diisocyanate, p-phenylene diisocyanate, 2,6-tolylene diisocyanate, 2,4-tolylene diisocyanate, and naphthalene-1,4. -Diisocyanate, diphenylmethane-4,4'-
Diisocyanate, 3,3'-dimethoxy-4,4'-biphenyl-diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, xylylene-1,4-
Diisocyanate, 4,4'-diphenylpropane diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate, propylene-1,2-diisocyanate, butylene-1,2-diisocyanate, cyclohexylene-1,2-diisocyanate, cyclohexylene-1, Diisocyanates such as 4-diisocyanate, 4,
Triisocyanates such as 4 ', 4 "-triphenylmethane triisocyanate, toluene-2,4,6-triisocyanate, 4,4'-dimethyldiphenylmethane-2,
Tetraisocyanate such as 2 ', 5,5'-tetraisocyanate, adduct of hexamethylene diisocyanate and trimethylolpropane, adduct of 2,4-tolylenediisocyanate and trimethylolpropane, addition of xylylenediisocyanate and trimethylolpropane Stuff,
There are isocyanate prepolymers such as adducts of tolylene diisocyanate and hexanetriol.

Examples of the polyol as the second wall film forming substance include aliphatic and aromatic polyhydric alcohols, hydroxypolyesters, and hydroxypolyalkylene ethers. Preferred polyols include polyhydroxy compounds having the following groups (I), (II), (III) or (IV) in the molecular structure between two hydroxyl groups and having a molecular weight of 5000 or less.

(I) an aliphatic hydrocarbon group having 2 to 8 carbon atoms Here, Ar of (II), (III) and (IV) represents a substituted or unsubstituted aromatic moiety, and the aliphatic hydrocarbon group of (I) means -C _n H _2n- And the hydrogen group may be replaced by another element.

Specific examples thereof include, as examples of (I), ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and 1,7-hexanediol. Heptadinol, 1,8-octanediol,
Propylene glycol, 2,3-dihydroxybutane, 1,2
-Dihydroxybutane, 1,3-dihydroxybutane, 2,2
-Dimethyl-1,3-propanediol, 2,4-pentanediol, 2,5-hexanediol, 3-methyl-1,5-pentanediol, 1,4-cyclohexanedimethanol,
Dihydroxycyclohexane, diethylene glycol,
Examples thereof include 1,2,6-trihydroxyhexane, phenylethylene glycol, 1,1,1-trimethylolpropane, hexanetriol, pentaerythritol, and glycerin.

Examples of (II) include condensation products of aromatic polyhydric alcohols such as 1,4-di (2-hydroxyethoxy) benzene and resorcinol dihydroxyethyl ether with alkylene oxides.

Examples of (III) include p-xylylene glycol,
m-xylylene glycol, α, α'-dihydroxy-
p-Diisopropylbenzene and the like.

Examples of (IV) include 4,4'-dihydroxy-diphenylmethane, 2- (p, p'-dihydroxydiphenylmethyl) benzyl alcohol, an adduct of ethylene oxide with bisphenol A, and propylene oxide with bisphenol A. And adducts. The polyol has a hydroxyl group ratio of 0.02 to 1 mol per isocyanate group.
It is preferred to use 2 moles.

When making microcapsules, a water-soluble polymer can be used, but the water-soluble polymer may be any of a water-soluble anionic polymer, a nonionic polymer, and an amphoteric polymer. Examples of the anionic polymer, either natural can be used even be synthetic, for example -COO ^-, -SO ₃ ^- include those having a group. Specific anionic natural polymers include arabic gum, alginic acid, and the like.
Semi-synthetic products include carboxymethyl cellulose, phthalated gelatin, sulfated starch, sulfated cellulose, and ligninsulfonic acid.

Examples of synthetic products include maleic anhydride (including hydrolyzed) copolymers, acrylic acid (including methacrylic acid) polymers and copolymers, vinylbenzenesulfonic acid polymers and copolymers, Modified polyvinyl alcohol and the like.

As the nonionic polymer, polyvinyl alcohol,
Examples include hydroxyethyl cellulose and methyl cellulose.

 Examples of the amphoteric compound include gelatin.

These water-soluble polymers are used as a 0.01 to 10% by weight aqueous solution. The particle size of the microcapsules is adjusted to 20 μ or less. Generally, when the particle size exceeds 20 μm, the print quality tends to be inferior.

In particular, when heating with a thermal head is performed from the coating layer side, the thickness is preferably 8 μm or less to avoid pressure fog.

The diazo compound, the coupling component and the basic substance used as the main components used in the present invention may be any one of those used as a core material of a microcapsule, or two kinds, or three kinds. Can be used. When two types are contained in the core material of the microcapsules, the same microcapsules or separate microcapsules may be used. When three kinds are contained in the core material of the microcapsule, three kinds cannot be contained simultaneously in the same microcapsule, but there are various combinations. Other components not contained in the core material of the microcapsule are used in the heat-sensitive layer outside the microcapsule.

The α-aryloxyacetamide derivative of the present invention may be on or outside the core of the microcapsule.

When making microcapsules, they can be made from emulsions containing 0.2% by weight or more of the components to be microencapsulated.

The diazo compound, the coupling component, and the optional basic substance used in the present invention are contained in 1 part by weight of the diazo compound, whether contained in the microcapsule or in the thermosensitive layer outside the microcapsule. On the other hand, it is preferable to use 0.1 to 10 parts by weight of the coupling component and 0.1 to 20 parts by weight of the basic substance. The diazo compound is preferably applied at 0.05 to 5.0 g / m ² .

When the diazo compound, the coupling component, and the basic substance used in the present invention are not microencapsulated, they are preferably used as a solid dispersion with a water-soluble polymer by a sand mill or the like. Preferred water-soluble polymers include water-soluble polymers used for making microcapsules. At this time, the concentration of the water-soluble polymer is 2 to 30 wt%,
The diazo compound, the coupling component, and the basic substance are added to the water-soluble polymer solution at 5 to 40% by weight, respectively.

 The size of the dispersed particles is preferably 10 μm or less.

In the heat-sensitive recording material of the present invention, various compounds such as ether, phenol, sulfonamide, carboxylic amide, ester, and ketone may be used in combination with the α-arylacetamide derivative of the present invention for the purpose of further improving thermochromic properties. Good.

Specific examples include 2-benzylkoxynaphthalene, 1
-P-biphenyloxy-2-phenylethane, 2-benzoyloxynaphthalene, 2-phenoxyacetyloxynaphthalene, 2-p-chlorobenzyloxynaphthalene, 1-hydroxy-2-phenoxycarbonylnaphthalene, 1,4-bis Phenoxybutane, 1,2-bis-m-
Tolyloxyethane, 1-phenoxy-2-p-ethylphenoxyethane, 1,2-diphenoxyethane, 1-phenoxy-2-p-chlorophenoxyethane, bis (phenoxyethyl) oxalate, 1-phenoxy- 2-
p-methoxyphenoxyethane, β-chloroethoxynaphthalene, 1-phenoxy-2-p-tolyloxyethane, bis (phenoxyethyl) carbonate, biphenyl-β-methoxyethyl ether, p-biphenyl-β
-Cyclohexyloxyethyl ether, β-cyanoethoxynaphthalene, β-chloroethoxy-p-biphenyl, 2-phenoxyphenyloxycarbonylphenol, 2-p-biphenyloxycarbonylphenol,
2-β-naphthyloxycarbonylphenol, bis (2-p-methoxyphenoxyethyl) ether, bis (2-p-ethoxyphenoxyethyl) ether, bis (2-p-methoxyphenoxyethoxy) methyl Ether, ether such as 1,2-bis-4-methoxythiophenoxyethane, or butylphenol, pt-octylphenol, p-α-cumylphenol, pt-
Pentylphenol, 2,5-dimethylphenol, 2,4,5
-Trimethylphenol, 3-methyl-4-isopropylphenol, p-benzylphenol, o-cyclohexylphenol, p- (diphenylmethyl) phenol, p (α, α-diphenylethyl) phenol, o-
Phenylphenol, ethyl p-hydroxybenzoate,
Chloropyl p-hydroxybenzoate, butyl p-hydroxybenzoate, benzyl p-hydroxybenzoate, p-
Methoxyphenol, p-butoxyphenol, p-heptyloxyphenol, p-benzyloxyphenol, 3-hydroxyphthalic acid, dimethyl vanillin, 2,5
-Diethylphenol, 1,1-bis (4-hydroxyphenyl) dodecane, 1,1-bis (4-hydroxyphenyl) -2-ethyl-hexane, 1,1-bis (4-hydroxyphenyl)- 2-methyl-pentane, 2,2-bis (4-hydroxyphenyl) -heptane, vanillin, 2
-T-butyl-4-methoxyphenol, 2,6-dimethoxyphenol, 2,2'-dihydroxy-4-methoxybenzophenone, β-resorcinic acid phenoxyethyl ester, orseric acid-α-methylbenzyl ester,
Phenols such as methyl hydroxycinnamate or ethylbenzenesulfonamide, toluenesulfonamide, methoxybenzenesulfonamide, ethyltoluenesulfonamide, chloroethoxybenzenesulfonamide,
(Iso) propylbenzenesulfonamide, ethoxytoluenesulfonamide, t-amylbenzenesulfonamide, diethylbenzenesulfonamide, allylbenzenesulfonamide, ethoxybenzenesulfonamide,
Sulfonamides such as cyclohexylbenzenesulfonamide, or benzamide, m-methoxybenzamide, methylbenzamide, ethylbenzamide, isopropylbenzamide, butylbenzamide, t-amylbenzamide, cyclohexylbenzamide, dimethylbenzamide, Nicotinamide, picolinamide,
Naphthamide, phenylbenzamide, chlorobenzamide, o-chlorobenzamide, methoxychlorobenzamide, methoxytoluamide, ethoxybenzamide,
Butylbenzamide, dimethylnaphthamide, trimethylbenzamide, dimethylchlorobenzamide, dimethoxychlorobenzamide, dimethoxybenzamide, diethoxybenzamide, pivaloylamide, 2-ethylhexanoamide, p-acetoxybenzamide, diethylaminobenzamino, Examples include phthalamide, methoxycarbonylbenzamide, methoxynaphthamide, benzylbenzamide, chloroethylbenzamide, chloroethoxybenzamide, cyanobenzamide, benzyloxybenzamide and the like.

These compounds can be used in the form of microcapsules together with the core material of the microcapsules, or added to the coating solution of the heat-sensitive recording material and used outside the microcapsules. Is preferred. In each case, the amount used is 0.01 to 10 parts by weight, preferably 0.1 part by weight, per 1 part by weight of the coupling component.
The amount is 1 to 5 parts by weight, but may be appropriately selected in order to adjust to a desired color density.

To the heat-sensitive recording material of the present invention, a free radical generator (a compound that generates free radicals by light irradiation) used in a photopolymerizable composition or the like for the purpose of reducing yellowing of the background after light fixing is added. Can be. Examples of the free radical generator include aromatic ketones (for example, benzophenone, 4,4'-bis (dimethylamino) benzophenone, 4,4'-bis (diethylamino) benzophenone, 4-methoxy-4 '(dimethylamino) benzophenone, 4,4'-dimethoxybenzophenone, 4-dimethylaminobenzophenone, 4-methoxy-3,3'-dimethylbenzophenone, 1-hydroxycyclohexylphenylketone, 4-dimethylaminoacetophenone, 2- Methyl-1- [4- (methylthio) phenyl] -2-morpholino-propanone-1-acetophenone-benzyl), cyclic aromatic ketones (for example, fluorenone, anthrone, xanthone, thioxanthone, 2-chlorothioxanthone, 2,4 -Dimethylthioxanthone, 2,4-diethylthioxanthone, Emissions, N- ethyl acridone, benzanthrone), quinones (e.g., benzoquinone, 2,3,5-trimethyl -
6-bromobenzoquinone, 2,6-di-n-decylbenzoquinone, 1,4-naphthoquinone, 2-isopropoxy-1,4
-Naphthoquinone, 1,2-naphthoquinone, anthraquinone, 2-chloro-anthraquinone, 2-methylanthraquinone, 2-tert-butylanthraquinone, phenanthraquinone), benzoin, benzoin ethers (for example, benzoin methyl ether, benzoin ethyl ether, 2,2-dimethoxy-2-phenylacetophenone,
α-methylol benzoin methyl ether), aromatic polycyclic hydrocarbons (eg, naphthalene, anthracene, phenanthrene, pyrene), azo compounds (eg, azobisisobutyronitrile, α-azo-1-cyclohexanecarbonitrile) Azobisvaleronitrile), organic disulfides (eg, thiuram disulfide), and acyl oxime esters (eg, benzyl- (o-ethoxycarbonyl) -α-monooxime).

The amount to be added is preferably 0.01 to 5 parts by weight of the free radical generator per 1 part by weight of the diazonium compound. More preferably, it is in the range of 0.1 to 1 part by weight.

By encapsulating the free radical generator together with the diazonium salt as a core material of the microcapsule, it is possible to reduce the yellowing of the background after the above-mentioned light fixing.

In the heat-sensitive recording material of the present invention, a polymerizable compound having an ethylenically unsaturated bond (hereinafter, referred to as a vinyl monomer) can be used for the purpose of reducing yellowing of the background after light fixing. A vinyl monomer is a compound having at least one ethylenically unsaturated bond (vinyl group, vinylidene group, etc.) in its chemical structure, and includes monomers, prepolymers, that is, dimers, trimers and other Oligomers have a chemical form such as mixtures thereof and copolymers thereof. Examples thereof include unsaturated carboxylic acids and salts thereof, esters of unsaturated carboxylic acids and aliphatic polyhydric alcohol compounds, and amides of unsaturated carboxylic acids and aliphatic polyamine compounds.

The vinyl monomer is 0.2 parts per 1 part by weight of the diazo compound.
Used at a rate of の 20 parts by weight. Preferably, the proportion is 1 to 10 parts by weight.

The vinyl monomer is used together with the diazo compound in the core material of the microcapsule. At this time, part or all of the organic solvent used as the solvent (or dispersion medium) of the core material can be replaced with the vinyl monomer. It does not need to be added to harden the material.

When a diazo compound is contained as a core substance in the heat-sensitive recording material of the present invention, a diazo compound present in an aqueous phase and a diazo compound in an incomplete capsule are contained by adding a coupling reaction deactivator outside the microcapsules. The compound (ie, a diazo compound that is not completely blocked by the capsule wall) reacts with the coupling reaction quenching agent, and the diazo compound loses the coupling reaction (coloring reaction) ability to prevent fogging. it can.

The coupling reaction quenching agent may be any substance that reduces the coloring of the solution in which the diazo compound is dissolved, and the diazo compound is dissolved in water or an organic solvent, and the other is dissolved in water or an organic solvent. Selection can be made by adding the compound and looking at the color change of the diazo compound.

Specifically, hydroquinone, sodium bisulfite,
Examples include potassium sulfite, hypophosphorous acid, stannous chloride, formalin and the like. In addition, "The Aroma" by KHSawn ders
tic Diazo-Compounds and Their Technical Applications "MC, MA (Cant ab.) B. Sc. (London)
It can also be selected from those described in pages 1105 to 306, published in 1949.

The coupling reaction quenching agent is preferably a quenching agent which itself has little coloring and has few side effects. More preferably, it is a water-soluble substance.

The coupling reaction quenching agent is used to such an extent that the thermal coloring reaction of the diazo compound is not hindered. Usually, the quenching agent is used in the range of 0.01 mol to 2 mol per 1 mol of the diazo compound. More preferably, it is used in the range of 0.02 mol to 1 mol.

The coupling reaction quenching agent of the present invention is dissolved in a solvent and then added to a liquid in which microcapsules containing a diazo compound are dispersed, or a liquid in which a coupling agent or a basic substance is dispersed, or a mixture thereof. Used. Preferably, the quenching agent is used in the form of an aqueous solution.

The heat-sensitive recording material of the present invention includes pigments such as silica, barium sulfate, titanium oxide, aluminum hydroxide, zinc oxide, and calcium carbonate, styrene beads, and urea for the purpose of preventing sticking to a heat head and improving writing properties. -Fine powders such as melamine resin can be used.

Similarly, metal soaps can be used to prevent stateing. The amount of these used is 0.
It is ² to 7 g / m2.

The thermal recording material of the present invention can be coated using a suitable binder.

Examples of binders include polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, hydroxypropyl cellulose, gum arabic, gelatin, polyvinyl pyrrolidone, casein, styrene-butadiene latex, acrylonitrile-butadiene latex, polyvinyl acetate, polyacrylate, ethylene-vinyl acetate. Various emulsions of polymers can be used. The amount used is 0.5-5 g / m ² of solids.

In the present invention, citric acid, tartaric acid, oxalic acid, boric acid, phosphoric acid, pyrophosphoric acid as an acid stabilizer in addition to the above materials
Can be added.

The heat-sensitive recording material of the present invention is prepared by preparing a coating solution containing a main component of a diazo compound, a coupling component, and a basic substance and other additives, and applying a bar onto a support such as paper or a synthetic resin film, using a blade. Coating, air knife coating, gravure coating, roll coating coating, spray coating, dip coating, etc.
A heat-sensitive layer of 5 g / m ² is provided. As another method, a coating liquid is prepared by adding a main component of a coupling component, a basic substance, and other additives as a core substance of a microcapsule, or dispersing a solid, or dissolving as an aqueous solution and then mixing. , Coated on a support and dried to obtain a solid content of 2.
Provided to 10 g / precoat layer of m ^2, mixed after further dissolving the diazo compound as the main component on the other additives or added as a core material of a microcapsule, or as or aqueous solution to a solid dispersion It is also possible to apply the prepared coating solution and dry it to form a laminated type provided with a coating layer having a solid content of 1 to 15 g / m ² . The layered thermosensitive recording material can be formed by reversing the order of lamination, and the coating method can be sequential coating or simultaneous coating. This laminated type thermosensitive recording material can provide particularly excellent performance in long-term raw preservability.

Further, after providing an intermediate layer described in Japanese Patent Application No. 59-177669 or the like on a support, a heat-sensitive layer can be applied.

As the paper used for the support, hot extraction pH 6 sized with a neutral sizing agent such as alkyl ketene dimer
The use of neutral papers Nos. 9 to 9 (described in JP-A-55-14281) is advantageous from the viewpoint of storage stability over time.

In order to prevent the coating liquid from penetrating into the paper and to improve the contact between the recording heat head and the heat-sensitive recording layer, see JP-A-57-116687.
No. In addition, paper having a smoothness of 90 seconds or more is advantageous.

The optical surface roughness described in JP-A-58-136492 is 8
paper having a density of 0.9 g / cm ³ or less and an optical contact ratio of 15% or more described in JP-A-58-69091, described in JP-A-58-69097. Canadian standard water level (J
Paper made from pulp beaten to 400 cc or more by IS P8121) to prevent the penetration of the coating solution, JP-A-58-65695
The glossy surface of the base paper made by the Yankee machine described in No. 1 is used as the coated surface to improve the color density and resolution.
The paper described in JP-A-59-35983, in which base paper is subjected to a corona discharge treatment to improve coating suitability, is also used in the present invention, and gives good results. Any of these other supports used in the field of ordinary thermosensitive recording paper can be used as the support of the present invention.

The heat-sensitive recording material of the present invention can be used as a printer paper for facsimile machines and electronic computers that require high-speed recording, and can be fixed by exposing and decomposing unreacted diazo compounds after heating and printing. .
In addition, it can be used as a heat development type copy paper.

"Examples" Examples will be shown below, but the present invention is not limited thereto. "Parts" indicating the amount of addition represents "parts by weight".

"Examples of the invention" Example 1 3.45 parts of the following diazo compound and 18 parts of a (3: 1) adduct of xylylene diisocyanate and trimethylolpropane were added to a mixed solvent of 24 parts of tricresyl phosphate and 5 parts of ethyl acetate, Dissolved. This diazo compound solution was mixed with an aqueous solution in which 5.2 parts of polyvinyl alcohol was dissolved in 58 parts of water, and emulsified and dispersed at 20 ° C. to obtain an emulsion having an average particle size of 2 μm. 100 parts of water was added to the obtained emulsion, and the mixture was heated to 60 ° C. with stirring, and after 2 hours, a capsule liquid containing a diazo compound in the core substance was obtained.

(Diazo compound) Next, 10 parts of 2-hydroxy-3-naphthoic acid anilide and 10 parts of triphenylguanidine were added to 100 parts of a 5% aqueous solution of polyvinyl alcohol and dispersed by a sand mill for about 24 hours, and a coupling component having an average particle diameter of 3 μm and triphenylguanidine were added. Was obtained.

Further, 20 parts of α- (2-methylphenoxy) acetamide were added to 100 parts of a 4% aqueous solution of polyvinyl alcohol and 100 parts of water, and dispersed in a paint shaker for 2 hours. The average particle size was 3 μm.
Was obtained.

Capsule liquid of diazo compound obtained as described above
To 50 parts of a coating liquid were added a coupling component, 24 parts of a dispersion of triphenylguanidine, and 28 parts of a dispersion of α- (2-methylphenoxy) acetamide. This coating solution was applied to a smooth high-quality paper (50 g / m ² ) using a coating bar to a dry weight of 10 g / m ² and dried at 25 ° C. for 30 minutes to obtain a heat-sensitive material.

Examples 2 and 3 The procedure of Example 1 was repeated, except that α- (3-methylphenoxy) acetamide and α- (4-methylphenoxy) acetamide were used instead of α- (2-methylphenoxy) acetamide. A heat-sensitive recording material was obtained.

Comparative Example 1 A heat-sensitive recording material was obtained in the same manner as in Example 1, except that α- (2-methylphenoxy) acetamide was replaced with α-phenoxyacetamide.

(Test method) Thermal recording was performed on the obtained thermal recording material using a GIII mode thermal printer (Hyfax 700; manufactured by Hitachi, Ltd.), and then the entire surface was recorded using Ricopy Super Dry 100 (manufactured by Ricoh). It was exposed and fixed. The blue density of the obtained recorded image was measured by a Macbeth reflection densitometer. The yellow density of the background was also measured.

In addition, in order to examine the raw preservability under high temperature and high humidity conditions, 60 ° C, 30% RH, 24 hours (dry thermo) and 40 ° C
Under the two conditions of 90 ° C., 90% RH and 24 hours (wet thermo), the coloring of the background (ground fog) was measured.

On the other hand, when thermal recording was again performed on the fixed portion, it was confirmed that no image was recorded and the image was fixed.

Next, in order to examine the decrease in the optical density of the colored portion due to long-term storage after thermal recording, the recorded image of
After storage for 16 hours in a dark place under the condition of ° C., the degree of decrease in the density of the recorded image after the forced deterioration test was evaluated.

As a result, in all of Examples 1 to 3, image density> 1.2, background yellow density <0.08, decrease in recorded image density after forced deterioration test <5%, dry thermochromic color <0.15,
It showed a wet thermo color of <0.15, and exhibited excellent properties as compared with those using α-phenoxyacetamide of Comparative Example 1.

The amount of α-phenoxyacetamide dissolved in 100 ml of water at 50 ° C. used in Comparative Example 1 was 2.8 g, whereas the amount of α- (methylphenoxy) acetamide in Examples 1 to 3 was any. Also weighed less than 1.5g.

From these results, it can be seen that the effect of the compound of the present invention is excellent in raw preservability, quick in thermal response, and effective in preserving recorded images.

Claims (1)

(57) [Claims] 1. A diazo compound, a coupling component and an α having a solubility in water at 50 ° C. of 1.5 g / 100 ml or less on a support.
-A heat-sensitive recording material carrying an aryloxyacetamide derivative.